1. Technical Field
The present invention relates to an integrated circuit device, an electronic appliance, and the like.
2. Related Art
It is known that motor drivers for driving DC motors and stepper motors use H-bridge circuits. An H-bridge circuit includes first to fourth driving transistors (switch elements), and the first and fourth transistors and the second and third transistors are electrically connected diagonally with respect to the motor. The first to fourth transistors are controlled so as to be on and off by a PWM signal from a pre-driver, and a drive current output by the bridge circuit varies according to the pulse width of the PWM signal.
In the case of driving a stepper motor, for example, 2-channel H-bridge circuits are used. A PWM signal from a first pre-driver is input into a first H-bridge circuit, and a PWM signal from a second pre-driver is input into a second H-bridge circuit. Then, the first H-bridge circuit causes a first drive current to flow between a first terminal and a second terminal of the stepper motor, and the second bridge circuit causes a second drive current to flow between a third terminal and a fourth terminal of the stepper motor. By switching the first drive current and the second drive current to predetermined current values in each step, the stepper motor is rotated by a predetermined angle each time one step is performed.
As a technique regarding two functional blocks and two control circuits such as 2-channel H-bridge circuits and pre-drivers described above, there is a technique disclosed in JP-A-02-50459. According to this technique, the two functional blocks are placed one above the other, and the two control circuits are placed on the right and left sides of the functional blocks. According to the invention, each H-bridge circuit is driven by a single pre-driver, but according to the technique disclosed in JP-A-02-50459, each control circuit is connected to the two functional blocks.